A shell of debris
What Happens to Old Satellites?
Dead satellites and fragments keep orbiting for years, and at orbital speed even a fleck is dangerous.
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Step 1 of 5
A dead satellite does not simply drop.
Switching off changes nothing about its orbit, so a satellite that stops working carries on circling exactly as before, silent and uncontrolled.
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Step 2 of 5
At orbital speed, even a fleck is dangerous.
Debris travels around eight kilometres a second. A chip of paint at that speed carries the punch of a bullet and can crack a window.
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Step 3 of 5
Every collision multiplies the problem.
When two objects hit, they do not simply stop. They shatter into thousands of fragments, each on its own orbit and each now a hazard.
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Step 4 of 5
Low orbits clear themselves, slowly.
There are still faint traces of atmosphere low down, which gradually drag objects until they re-enter and burn up. Higher orbits do not.
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Step 5 of 5
So operators now plan the ending.
New satellites carry enough fuel to either drop themselves into the atmosphere or climb to a graveyard orbit well out of the way.
Around 130 million fragments larger than a millimetre are thought to be in orbit, and even those are too small to track.
The short version
Dead satellites and fragments keep orbiting for years or centuries, and at orbital speed even tiny pieces are dangerous enough to matter.
Try it yourself
Look up a live map of tracked orbital debris. The shell of dots around Earth is denser than most people expect.
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